After power is applied to a chip, registers and memory elements in general on the chip will assume values that are unpredictable and will contain data that is invalid. When the chip is a processor, this is not problematic unless a program resident on the processor tries to read memory elements prior to known values having been written into the memory elements. This may be particularly problematic when programs use a memory element, such as a register, as a pointer to a memory. In the latter scenario, the pointer is invalid, and its use will lead to processing errors.
To prevent processing errors, there is a need for a mechanism to identify when a memory element, such as a register, has invalid data in it. There is a further need to flag registers that have invalid data in them to prevent these registers from being used as pointers to memory.